Do you have room for a reed bed treatment system before it goes to waterways? Plenty info on net. Also ypu could try a sand filtration system to treat it and reuse for garden. Can be an easy system and results are good it waters my garden with tub and bathroom sink a laundry water. It can be pumped directly into large trash can with gravity filtered and run back out by hose. mine works great. Havent had to fresh water the garden all season so far.
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